Tag: amplify air

Venturi Effect in Use

Published on by jasonkirbyLeave a comment

The Venturi effect describes the phenomenon where a fluid, such as air or water, accelerates as it passes through a constricted section, resulting in a decrease in pressure. This occurs because the fluid is drawn into the narrower area, and the increase in velocity leads to a corresponding drop in pressure. The effect is named after Giovanni Battista Venturi, who first articulated this principle in 1797.

A perfect example of the Venturi Effect can be found in our Air Amplifiers. Compressed air enters through the air inlet and flows into an annular chamber, where it is accelerated through a small ring nozzle. This high-velocity primary airstream follows the Coanda effect, guiding it toward the outlet. As a result, a low-pressure zone forms at the center, drawing in a significant volume of surrounding air into the primary flow. The mixture of the primary airstream and the surrounding air is then expelled from the Air Amplifier at a high volume and velocity.

The Venturi Effect is represented in amplification ratios. A ratio represents the relationship between two quantities, indicating how many times one value is contained within another. In the case of the Super Air Knife, this ratio illustrates the volume of ambient air that is drawn in alongside the primary flow of compressed air. With an impressive amplification ratio of 40:1, the Super Air Knife incorporates 40 parts of ambient air for every single part of compressed air, making it one of the most efficient air-operated knives available. This addition of mass enhances the device’s ability to deliver a powerful force, enabling it to perform more effectively in various applications.

The Venturi effect is integral to various EXAIR products designed for cooling, drying, and cleaning, alongside our vacuum generators. If your facility has a process that could benefit from an Intelligent Compressed Air solution, please reach out to us. We would be pleased to discuss your specific application and develop a solution that not only lowers your compressed air expenses but also enhances worker safety.

Jason Kirby
Application Engineer
Email: jasonkirby@exair.com
Twitter: @EXAIR_jk

Amplification Ratio: Super Air Knives

Published on by John BallLeave a comment
Super Air Knife

Earlier, I wrote a blog about how entrainment works with EXAIR products by using two phenomena, Coanda Profile and the Venturi Effect.  You can find it here, “Entrainment: how it works and why EXAIR products use it.”  In this blog, I will cover the Super Air Knife specifically and how it uses the Venturi Effect to entrain the surrounding air. 

This Venturi Effect is named after Giovanni Venturi, who discovered that by increasing the velocity through an orifice, the surrounding fluid will move with it, generating a lower pressure.  The higher the velocity, the lower the pressure.  When you have a low pressure, the surrounding air will fill that void and move into the airstream.  The amount of ambient air that gets “pulled” into the airstream is the entrainment, and this amount as compared to the inlet flow is the Amplification Ratio. 

So, what does this mean?  The definition of a ratio is the relationship between two amounts showing the number of times one value is contained within the other.  For the Super Air Knife, it is a value that shows the amount of ambient air that is drawn in along with the primary, compressed air flow.  With an amplification ratio of 40:1, that means that there are 40 parts of ambient air for every 1 part of compressed air, which helps make them the most efficient compressed air operated Air Knives available on the market.  By adding mass, the Super Air Knife will give a hard-hitting force to do more “work”. 

Most people think that compressed air is free, but it is most certainly not.  Because of the amount of electricity required to produce compressed air, it is considered to be a fourth utility for manufacturing plants.  To save on utility costs, it is important to use compressed air as efficiently as possible.  So, the higher the amplification ratio, the more efficient the compressed air product.  Manufacturing plants that use open fittings, copper tubes, and drilled pipes for blowing are not efficient.  These types of products generally have a very low amplification ratio, somewhere between 2:1 to 5:1.  When EXAIR began manufacturing in 1983, we knew that there was a better way of saving compressed air by increasing the amplification ratios of our various air moving products.

I like to explain things in everyday terms.  For this analogy, we can use the amplification ratio as represented by gas mileage.  Like your car, you want to get the most distance from a gallon of gas.  With your compressed air system, you want to get the most utilization for the compressed air being expended.  With an EXAIR Super Air Knife, it has a 40:1 amplification ratio; or, in other words, you can get 40 MPG.  But, if you use drilled pipes, copper tubes, etc. for blowing, then you are only getting 2 to 5 MPG, so to say.  If you want to get the most “mileage” for the money you spend on creating compressed air, you want to check the “fuel efficiency” of your blow-off components.

EXAIR manufactures many blow-off items with high amplification ratios to save compressed air. EXAIR can help “tune up” your blow-off systems to make them efficient and safe by contacting an Application Engineer.  We will be happy to help you.  

John Ball
Application Engineer
Email: johnball@exair.com
Twitter: @EXAIR_jb

“Free” Ambient Air Entrainment w/ EXAIR’s Super Air Amplifiers

Published on by Tyler DanielLeave a comment

When working with a cooling application, many customers will immediately look to the Vortex Tube and Spot Cooling product lines. While this may be the best solution for some applications, cold air is not always the best method that we have available for cooling. EXAIR’s Super Air Amplifiers are very effective at reducing the temperature of a part without requiring cold air. The Super Air Amplifiers get their name due to their ability to entrain ambient air and “amplify” the supplied compressed air. You’ll often see us referring to the air amplification ratios achieved with our products. This is a ratio of the supplied compressed air relative to the entrained “free” air that comes from the ambient environment.

Due to their ability to entrain large amounts of ambient air, we can move a high volume of air across the surface of the part and quickly lower the temperature. I like to compare this to blowing on a hot cup of coffee just as it’s been brewed. The temperature of the air coming from your mouth is around 98.6°F, the same as your body temperature. Coffee can be as hot as 185°F when fresh. Due to the temperature differential between your breath and the hot coffee, we’re able to achieve a reasonable amount of cooling just by simply blowing across the surface. Typically, when the target temperature of the part or material needs to be around ambient temperature or higher; the best solution for cooling is going to be a Super Air Amplifier.

EXAIR’s Super Air Amplifiers achieve air amplification ratios ranging from 12:1 on our smallest units and up to 25:1 for our 4” and 8” models. EXAIR’s Super Air Amplifiers utilize a patented shim design to maintain critical positioning of component parts. This allows a precise amount of compressed air to be released at exact intervals toward the center of the Super Air Amplifier. This creates a constant, high velocity outlet flow across the entire cross-sectional area. Free, ambient air is entrained through the unit, resulting in high amplification ratios. The balanced outlet airflow minimizes wind shear to produce sound levels far lower than other similar air movers.

Super Air Amplifiers are supplied with a .003” thick shim that is ideal for most applications. Flow and force can be increased by replacing the shim with a thicker .006” or .009” shim. The flow of air is also controlled by adjusting the input pressure supplied to the amplifier. Higher pressures increase both the force and flow, while lower pressures decrease both force and flow. All Super Air Amplifiers are available in kits that come with a shim set as well as a suitably sized pressure regulator and auto-drain filter.

EXAIR has a solution for you if you need to move A LOT of air. Reach out to an Application Engineer today if you have an application that you believe could be served with a low-cost, simple solution!

Tyler Daniel
Application Engineer
E-mail: TylerDaniel@EXAIR.com
Twitter: @EXAIR_TD